Dehydrated potato flakes

ABSTRACT

Dehydrated potato flakes prepared from potato slices, slivers and/or nubbins suitable for use in dough compositions used to make fabricated products. The dehydrated flakes are prepared such that the physical properties in the flake are controlled during processing. The resulting flakes can be used to prepare a more cohesive, non-adhesive, machineable dough.

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. ProvisionalApplication No. 60/022,521 filed Jul. 1, 1996 and U.S. ProvisionalApplication No. 60/020,936 filed Jul. 1, 1996.

TECHNICAL FIELD

[0002] This invention relates to dehydrated potato flakes and to amethod of preparing dehydrated potato flakes.

BACKGROUND OF THE INVENTION

[0003] Fabricated farinaceous products prepared from starch-based floursare well known in the art. Preparing such products from dehydratedingredients offers certain advantages such as homogeneity, uniformityand control of the end product. The food processor encounters severalproblems when formulating doughs used to prepare such products. Forexample, although a cohesive sheetable dough may be formed, the doughtypically falls apart or tears when sheeted at high speeds.Additionally, variability in the physical properties of the dehydratedingredients, in particular the flakes, often produces doughs that aresticky, tacky or gummy. This often leads to down time on processinglines and additional ingredient costs.

[0004] There are several problems associated with the physicalproperties of conventional potato flakes and with the processes used tomake such flakes. One significant problem with conventional flakes isrelated to the variability in the physical properties of the flakesproduced from potatoes. These variations are influenced by many factorssuch as types of potatoes used to make the flakes, the season in whichthe potatoes are grown, when the potatoes are harvested, the area wherethe potatoes are grown, and the length of time the potatoes are stored.These variations, up to now, have resulted in large variability betweenflake lots made from the potatoes.

[0005] The physical properties necessary in a flake used to formulate adough for making fabricated farinaceous products have gone unrecognizedor unappreciated. While conventional processes try to minimize brokencells, it has been found that flakes comprising from about 40% to about60% broken cells are desirable from a sheeting standpoint. Further, ithas been found that controlling the difference between hot pasteviscosity and cold paste viscosity improves processability, even thoughconventional processes do not place any importance on this particularphysical property. It has also been found that a low water absorption isdesirable in a flake used for making a dough. While conventionalprocesses suggest a high water absorption index is desirable.

[0006] Conventional methods for processing potatoes into dehydratedproducts have not allowed potato processors to produce suitable flakesfrom potatoes of different variety, different compositions or frompotato by-products (e.g., potato pieces left over from French fryprocesses) or potatoes from the beginning and end of season. Even whenthe same variety of potatoes are used, there is an inability toconsistently control the physical properties of the flakes byprocessing.

[0007] Several processes for making dehydrated potato flakes aredisclosed in U.S. Pat. No. 2,787,533 issued to Cording et al., U.S. Pat.No. 3,009,817 issued to Hendel, and U.S. Pat. No. 3,968,260 issued toShatilla et al. These patents disclose a process for preparing flakesfrom raw whole potatoes or conventional potato flakes but not fromslivers and nubbins. Further, these processes provide very few, if any,special measures that are designed to assure limited variability in thephysical properties of flakes. For example, prior to being cooked, thepotatoes are often pre-conditioned. The blanching toughens the potatocells, requires more energy to thoroughly cook the potatoes and makesuniform cooking of the potato pieces difficult. Additionally, thesequence of blanching, cooling, and cooking, as suggested by manyprocesses, increases retrogradation of starch and restricts the releaseof amylose and/or causes complexation of the free starch needed to forma cohesive machineable dough sheet. Moreover, cooking at hightemperatures and/or high steam pressures for short times or even at 212°F. (100° C.) for short times can result in potato flakes that areunder-cooked (e.g. raw or cooked on the outer surface) or over-cooked(e.g. having weak, swollen cells that will rupture during subsequentprocessing).

[0008] One process disclosed in U.S. Pat. No. 4,241,094 issued toO'Neal, makes dehydrated flakes by separating potatoes into two groupsduring the initial processing. Later the two groups of flakes areblended to make dehydrated flakes, which have a texture and qualitysimilar to freshly prepared mashed potatoes when reconstituted.According to the O'Neal patent, potato flakes made from mash having freestarch throughout are pasty and undesirable. Further, retrogradation ofstarch is encouraged. Although the flakes may be suitable for theconsumer to prepare mashed potatoes, the potato flakes, due to their lowlevel of free starch (amylose) and high water absorption index, are notdesirable for the production of doughs from which fabricated farinaceousproducts are made.

[0009] It can be seen that conventional processes are unsatisfactory formaking or providing dehydrated flakes having desirable properties.

[0010] A need exists for potato flakes made from various potatoes andpotato by-products. Another need exists for potato flakes havingcontrolled physical properties that are suitable for use in makingfarinaceous fabricated products. Further, a need exists for potatoflakes and for a method of producing potato flakes wherein thedifferences in performance from lot to lot is minimized.

[0011] Accordingly, it is an object of the present invention to providea process for making dehydrated potato flakes.

[0012] It is another object of the present invention to provide potatoflakes particularly suitable for doughs used to make fabricatedfarinaceous products.

[0013] It is further an object of the present invention to providepotato flakes having substantially improved processing qualities overconventionally-produced flakes.

[0014] These and other objects of the invention will become apparentfrom the following disclosure and claims.

BRIEF DESCRIPTION OF DRAWINGS

[0015]FIG. 1 is a graph showing the sheet strength test of a dough madefrom the potato flakes of the present invention;

[0016]FIG. 2 is a graph showing the sheet strength test of a dough madefrom conventional the potato flakes;

[0017]FIG. 3 is a photomicrograph magnification 64X of potato cells inflakes made according to the present invention.

[0018]FIG. 4 is a photomicrograph magnification 64× of potato cells inflakes made according to conventional methods.

[0019]FIG. 5 is a graph showing the effects of various cookingconditions including overcooking, undercooking and even cooking on thehot and cold paste viscosities of potato flakes.

SUMMARY OF THE INVENTION

[0020] The present invention relates to dehydrated potato flakes thatcan be prepared from potato slices, slivers and/or nubbins. The presentinvention further relates to a process for producing potato flakeswherein the cooking cycle, during processing of the potato flakes, iscontrolled.

[0021] The process of the present invention is advantageous overprocesses in that it allows the potato flake processor to produce flakesfrom potatoes of different varieties and compositions and additionallyto reduce the variability in the physical properties of the flakesproduced from potatoes of different varieties and compositions. Itfurther allows the flake producer to use slivers and nubbins, which wereonce thought to be unsuitable for use in the flaking process.

[0022] Use of the dehydrated flakes in the formulation of fabricatedfarinaceous products increases efficiency and allows the food processorto control the texture of the dough as well as the texture of theready-to-eat product.

[0023] In addition, the present invention relates to a dough containingthe dehydrated potato flakes. The dough has increased sheet strength andcan be used to prepare farinaceous fabricated food products.

DETAILED DESCRIPTION

[0024] Definitions

[0025] As used herein, the term “slivers” refers to thin sliced potatopieces that are separated from the products after the potato is cut intoFrench fry strips. These pieces are generally the by-products from thelength portion of the French fry strip and are typically shorter thanthe French fry itself.

[0026] As used herein the term “nubbins” refers to short or brokenpotato pieces that are separated from the potato after it is cut intoFrench fry strips. These pieces are generally the by-products from theend portions of the French fry strip.

[0027] As used herein, “Brabender Units (BU)” is an arbitrary unit ofviscosity measurement roughly corresponding to centipoise.

[0028] As used herein, the term “fabricated farinaceous products” refersto food products made from doughs that contain flour, meal or starchderived from tubers and/or grains.

[0029] As used herein “sheetable dough” is a dough capable of beingplaced on a smooth surface and rolled to the desired final thicknesswithout tearing or forming holes.

[0030] As used herein “starch-based materials” refer to naturallyoccuring, high polymeric carbohydrates composed of glucopyranose units,in either natural, dehydrated (e.g., flakes, granules, meal) or flourform. The starch-based materials include, but are not limited to, potatoflour, potato granules, corn flour, masa corn flour, corn grits, cornmeal, rice flour, tapioca, buckwheat flour, rice flour, oat flour, beanflour, barley flour, tapioca, as well as modified starches, nativestarches, and dehydrated starches, starches derived from tubers, legumesand grain, for example cornstarch, wheat starch, rice starch, waxy cornstarch, oat starch, cavassa starch, waxy barley, waxy rice starch,glutinous rice starch, sweet rice starch, amioca, potato starch, tapiocastarch, cornstarch, oat starch, cassaya starch, rice starch, wheatstarch, and mixtures thereof.

[0031] As used herein “Brabender Units (BU)” is an arbitrary unit ofviscosity measurement roughly corresponding to centipoise.

[0032] As used herein, “modified starch” refers to starch that has beenphysically or chemically altered to improve its functionalcharacteristics. Suitable modified starches include, but are not limitedto, pregelatinized starches, low viscosity starches (e.g., dextrins,acid-modified starches, oxidized starches, enzyme modified starches),stabilized starches (e.g., starch esters, starch ethers), cross-linkedstarches, starch sugars (e.g. glucose syrup, dextrose, isoglucose) andstarches that have received a combination of treatments (e.g.,cross-linking and gelatinization) and mixtures thereof.

[0033] As used herein, the term “added water” refers to water which hasbeen added to the dry dough ingredients. Water which is inherentlypresent in the dry dough ingredients, such as in the case of the sourcesof flour and starches, is not included in the added water.

[0034] All percentages are by weight unless otherwise specified.

[0035] The present invention relates to a dehydrated potato flake havingcertain physical properties. Sheet strength, water absorption andstickiness of the dough can be controlled by the addition of thedehydrated flakes to the dough. Controlling the physical properties ofthe flakes allows one to also control the texture and fat content of theready-to-eat fabricated farinaceous product without adding additionalingredients (e.g., fibers, gums).

[0036] Any commercially-available potato used to prepare flakes can beused to prepare the dehydrated flakes of the present invention.Preferably, the flakes are prepared from potatoes such as, but notlimited, to Kennebec, Russet Burbank, Idaho Russet, Sebago, Bentgie,Aurora, Saturna, and Mentor. Raw or pre-conditioned potato slices,nubbins and slivers or mixtures thereof can be used in the practice ofthe present invention. Typically, the nubbins and slivers will bepre-conditioned since they are by-products of a standard French frymaking process. The potato flakes can be made using standard potatoflake-making equipment, such as a twin or single screw cooker.

[0037] Potato pieces, as used herein “potato pieces” refer to potatoby-products, e.g. slivers, nubbins, or slabs can be used in the practiceof the present invention. In one preferred embodiment, raw potatoes arepeeled by steam and then inspected to remove defective potatoes. Thepeeling can be accomplished by lye, steam, or abrasion. The peeledpotatoes are sliced to a thickness of from about 0.25 to about 0.75inches, preferably from about 0.3 to about 0.7 inches and morepreferably from about 0.35 to about 0.65 inches (hereinafter referred toas “slabs”).

[0038] Next the raw potato pieces/slabs are cooked under atmosphericpressure using steam typically having a pressure of about 2 to about 20psig (pounds per square inch gauge), preferably from about 5 to about 18psig, and more preferably from about 10 to about 15 psig. The cookingprocess is critical to obtaining the desired potato flake. The length oftime to conduct the steaming and the cooking is, of course, dependentupon the volume capacity of the vessel, the steam generator output, andthe amount of potato pieces/slabs being cooked. Preferably thetemperature of the potato slab/pieces rises from about 65° F. (18° C.)to about 212° F. (79° C.) during the first one-third of the cookingcycle, and then maintained at a temperature 212° F. (79° C.) during theremainder of the cooking cycle. For example, if the total cooking timeis 30 minutes, it is important that the potato slabs/pieces receive aslow temperature rise in the first 10 minutes. It is also important thatthe potato slabs receive even cooking, and that the heating iscontinuous during at least the first one-third of the cooking cycle.Preferably, the heating is continuous throughout the cooking cycle andthe potatoes are not allowed to cool until cooking is complete. Thiswill allow the potato granules to sufficiently cook, swell, andgelatinize and will also allow some cells to shrink thereby increasingcell separation. Microscopic observations of potato cells frompieces/slabs that are prepared by heating the potato rapidly during thefirst one-third of the cooking cycle show that a case hardened surfaceforms on the outer portion of these potato cells and does not allow thepotato cells to swell properly. As temperature and pressure isincreased, the starch granules in the potato cells swell, gelatinize andburst [FIG. 4]. This results in flakes having a high water absorptionindex and low amylose content. If the potato pieces/slabs areundercooked, large amounts of raw starch can be seen in the microscopicobservation. Additionally, overcooked potato pieces/slabs show weakenedpotato cell walls which burst during subsequent processing. (Amylose istrapped within the gelatinized amylopectin structure.) This results inflakes having a measurable low level of soluble starch and high wateradsorption indexes. This is undesirable since high levels of gelatinized(amylopectin) starch will produce a sticky dough and since water will beremoved during subsequent cooking when the final farinaceous foodproduct is made. By contrast, microscopic evaluations of potatoespieces/slabs cooked by slowly raising the temperature during the firstone-third of the cooking cycle according to the present invention showswollen granules, cell separation and less than 60% broken cells [FIG.3].

[0039] The rate at which the potato pieces/slabs are heated during thefirst one-third of the cooking cycle and the distribution of the steamis important as it affects the properties of the resulting dehydratedflakes. Preferably, the temperature rise from about 175° F. (79° C.) toabout 212° F. (100° C.) occurs over a time period more than about 10minutes, more preferably in more than about 15 minutes and even morepreferably in more than about 20 minutes. The total cooking time is atleast about 30 minutes, preferably from about 30 to about 65 minutes,and more preferably from about 50 to about 60 minutes.

[0040] The potato pieces/slabs can also be cooked using a pressurizedvessel or Superheated steam. The steam temperatures and pressures canvary depending on the equipment used. However, it is important that theresulting cooked potato pieces have swollen granules, cell separationand less than 60% broken cells.

[0041] After the steam cooking, the potato pieces/slabs are riced byforcing the potato pieces through a slotted plate. Care must be takennot to break the cell structure. Generally, at least about 0.1%emulsifier is added to the wet mash or cooked potatoes as a processingaid. Higher levels of up to about 3% of an emulsifier can also be added,if needed, to complex the amylose if the resulting mash is too sticky(e.g., too many broken cells due to overcooking). However, when thepotato pieces/slabs are processed according to the present invention,high levels of emulsifier (e.g. greater than 1%) should not be required.Preferably, the emulsifier is added to the mash upon exiting the ricerand prior to the flaking operation. The preferred emulsifier is adistilled monoglyceride and diglyceride of partially-hydrogenatedsoybean oil. Other emulsifiers suitable as processing aids in makingpotato flakes known in the art, e.g. lactylate esters, can also be used.

[0042] Additional ingredients can also be added to the wet mash toimprove the storage stability of the dehydrated potato flakes. Variousstabilizers and preservatives are usually employed to improve thestability and texture of the resulting flakes. For example, from about150 to about 200 parts per million (p.p.m.) of sulfite is provided inthe dry product. This is added to the wet mash usually as dry sodiumsulfite and sodium bisulfite and protects the flakes from darkeningduring processing and subsequent storage. Antioxidants such as BHA (2and 3-tert-butyl-4-hydroxy-anisole) and BHT(3,5-di-tert-butyl-4-hydroxytoluene) are added in an amount up to atotal of about 10 p.p.m. to prevent oxidative deterioration. Citric acidis generally added in a quantity sufficient to give about 90 p.p.m. inthe dried product to prevent discoloration caused by the presence offerrous ions. Ascorbic acid can also be added to warrant the initiallevel of vitamins.

[0043] The potato mash is then subjected to a drying and flakingoperation. Water may be added to the mash to increase heat transferduring drying. Suitable dryers can be selected from those well knowndrying devices such as fluidized bed dryers, scraped wall heatexchangers, drum dryers, and the like. A particularly preferred dryer isa drum dryer. The use of drum dryers is known in the potato industry.

[0044] When a drum dryer is used, the mash is fed to the top surface ofthe drum by conveying means. Small diameter unheated rolls progressivelyapply fresh potato mash to portions already on the drum, thus buildingup a sheet. Peripheral speed of the small rolls is the same as that ofthe drum, and after traveling around the circumference of the drum adoctor knife removes the dried sheet by peeling the dried sheet awayfrom the drum. Typically, the drum dryer itself is heated totemperatures within the range of from about 300° F. to about 380, ° F.preferably to a temperature of from about 330° F. to about 356° F. bypressurized steam contained within the drum at pressures of from about100 psig to about 132 psig. For optimum results the rotational speed ofthe dryer drum and the internal temperature thereof is suitablycontrolled so as to give a final product having a moisture content offrom about 5% to about 10%. Typically, a rotational speed of from about2 rpm to about 6 rpm, preferably about 2 rpm to about 4.5 rpm, issufficient.

[0045] The preferred process utilizes a twin double drum drier whereinthe wet potato mash is spread on the drum in a thin sheet having athickness of from 1 to about 5, preferably from about 4 to about 5,times the thickness of a single potato cell in an undried state, orabout 0.007 to about 0.010 inches.

[0046] Once the wet mash is sheeted and dried, the resulting dried sheetis then comminuted with for example, an Urschel Comitrolu, manufacturedby Urschel Laboratories, Inc. of Valparaiso, Ind. Any method ofcomminution that minimizes the starch damage, such as grinding, cuttingor pulverizing can be used.

[0047] The resulting dehydrated potato flakes comprise from 19% to about27% amylose, from about 5% to about 10% moisture, at least about 0.1%emulsifier and a water absorption index of from about 7.7 to about 9.5.

[0048] In another embodiment, potato flakes are made frompre-conditioned potato slabs, nubbins, and slivers or mixtures thereof.As used herein “pre-conditioned” refers to treatments such as blanching,water transporting which causes the cells to toughen. The dehydratedpotato flakes can be made from slivers and nubbins (herein after referto as “pieces”), as part or all of the potato ingredient, or the nubbinsand slivers can be mixed together with potato slabs in the cookingprocess. Typically, the nubbins and slivers will be blanched since theyare made in a standard French fry making process. The potato flakes canbe made from about 5% to about 100% slivers, nubbins and mixturesthereof, and from about 0% to about 95% other potato pieces, typicallyslabs. Generally from about 5% to about 100% slivers, nubbins andmixtures thereof are used and from 0% to 95% potato slabs are used.Preferably, from about 20% to about 90% slivers, nubbins and mixturesthereof and from about 10% to about 80% potato slabs; more preferablyfrom about 30% to about 80% slivers, nubbins and mixtures thereof andfrom about 20% to about 70% potato slabs; even more preferably fromabout 40% to about 70% slivers, nubbins and mixtures thereof and fromabout 30% to about 60% potato slabs; and especially preferably fromabout 50% to about 60% slivers, nubbins and mixtures thereof and fromabout 40% to about 50% potato slabs are used.

[0049] It has been found that blanching or pre-conditioning potatopieces/slabs cause the potato cells to toughen. As a result, when usingpre-conditioned potato pieces, additional energy is required to cook thepotato pieces properly (i.e., to obtain cooked potato pieces havingswollen granules, cell separation and less than 60% broken cells). Thepre-conditioning of the potato pieces/slabs causes the resulting potatoflakes to have a lower water absorption index (WAI), and measurableamylose content than potato flakes produced from potato pieces/slabsthat have not been pre-conditioned. However, the cooking process stillrequires controlling the rate at which the potato pieces are heatedduring the first one-third of the cooking cycle.

[0050] The increase in pressure and temperature needed to cookpre-conditioned potato pieces causes the resulting flakes to have alower water absorption index and a lower amylose content than potatoflakes produced from potato pieces that are not pre-conditioned prior tothe cooking.

[0051] The dehydrated potato flakes resulting from the process whereinthe potato pieces are pre-conditioned comprise from about 16% to about20% amylose, from about 5% to about 10% moisture, at least 0.1%emulsifier, and a water absorption index of from about 6.7% to about8.3%.

[0052] Therefore, within limits, the process of the present inventionallows one to produce end products having controlled and differentphysical properties which cannot be duplicated by potato flakes made byprior art process conditions.

Physical Properties of the Potato Flake

[0053] The potato flakes of the present invention have unique physicalproperties, in particular; (1) amylose content, (2) water absorptionindex, and (3) hot paste viscosity and cold paste viscosity. The methodsfor measuring the physical properties of the potato flakes are describedin the “Analytical Methods” disclosed below in the specification.

[0054] The potato flakes, when used in dough formulations, increase thecohesiveness, elasticity and sheeted strength of the dough.Additionally, use of the potato flakes of the present invention allowsthe food processor to control the amount of fat absorbed by the finishedproduct during cooking, if fried. This is surprising considering thefact that when conventional potato flakes are used in dough formulation,additional ingredients (e.g., binders, gums, and fibers) are required toachieve similar results. It is also surprising that the addition of thepotato flakes of the present invention to dough formulations improvesprocessability of the dough.

[0055] It has unexpectedly been found that improved processability ofthe dough is achieved partially by controlling the cold paste viscosityand hot paste viscosity. This produces flakes that are stable (e.g.,over various temperature ranges). In addition, it has also unexpectedlybeen found that the flakes of the present invention exhibitsubstantially improved color stability and resist viscosity changes overtime. These properties have not been exhibited by potato flakes producedby known processes.

[0056] The dehydrated potato flakes of the present invention comprisefrom about 40% to about 60% broken cells, from about 16% to about 27%amylose, from about 5% to about 10% moisture, and at least 0.1%emulsifier. Additionally, the dehydrated flakes of the present inventionhave a water absorption index of from about 6.7 to about 9.5 grams ofwater per gram of flakes, a hot paste viscosity of from about 100 BU toabout 320 BU and a cold paste viscosity of from about 100 BU to about200 BU. From about 40% to about 60% of the dehydrated potato flakesremain on a #40 U.S. screen.

Broken Cells

[0057] The dehydrated potato flakes of the present invention comprisefrom about 40% to about 60% broken cells, preferably from about 45% toabout 55% and more preferably about 50% broken cells. The percentage ofbroken cells is determined by light microscope and is an indication ofthe degree of cook and starch damage that has occurred during ricing andgrinding. A large number of broken cells indicate improper processingconditions, such as, overcooking, use of too much shear and/or reducingthe particle size of the potatoes by using an apparatus that applies toomuch shear,(e.g. a hammer mill) among other things.

Amylose—A (%)

[0058]

[0059] The dehydrated potato flakes also comprise from about 16% toabout 27% amylose (A %). The amylose is a measurement of the free starchin the potato flake composition. The level of amylose is controlled bymaintaining a slow but constant temperature rise during the first ⅓ ofthe cooking cycle and by controlling the grinding step of the potatoflaking process.

[0060] Dehydrated potato flakes made from raw potato pieces comprisefrom about 20% to about 27% amylose, preferably from about 22% to about25%, and more preferably about 21% to about 24% amylose.

[0061] Dehydrated potato flakes made from pre-conditioned, orunpre-conditioned but pre-conditioned flakes by transporting them incold water, potato pieces comprise from about 16% to about 20% amylose,preferably about from about 17% to about 19% amylose, and morepreferably about 18% amylose.

Moisture

[0062] The dehydrated potato flakes of the present invention comprisefrom about 5% to about 10%, preferably about 6% to about 9%, and morepreferably from about 7% to about 8% moisture.

Emulsifier

[0063] Typically an emulsifier is present in the flake because of itsuse as a processing aid to prevent the potato mash from sticking to theroller during drying and flaking. Therefore, low levels of emulsifiersare present in the flake. Typically the emulsifier is present in theflake at a level of from about 0.1% to about 1%. Preferably, theemulsifier is present in the flake at a level of from about 0.1% toabout 0.5%, more preferably at about 0.2% to about 0.4%. Higher levelsof emulsifiers can be present, for example, if the potatoes areovercooked and high levels of amylose are present in the potato mash. Inthese instances, the emulsifier may be present in a level as high as 3%.If the potato has been undercooked, the addition of emulsifiers will notcorrect the texture of the undercooked mash because of the large amountof raw starch.

Water Absorption Index (WAI)

[0064] Water absorption index is a physical parameter that indicates thecapacity of a material such as potato flakes to hold water. It isdirectly proportioned to the degree of cooking. It theoreticallycorrelates to the physical damage of the potato cells in the potatoflakes. WAI also correlates in a small degree to surface area exposed asa result of grinding. In the process of making fabricated chips, the WAIis believed to correlate to the level of fat that will be absorbed inthe final product during the frying process.

[0065] Dehydrated potato flakes made from raw potato pieces have a WAIof from about 7.7 to about 9.5 grams of water per gram of flakes,preferably from about 8 to about 9 grams of water per gram of flakes.

[0066] Dehydrated potato flakes that are made from pre-conditionedpotato pieces have a WAI of from about 6.7 to about 8.3, preferablyabout 7 to about 8, grams of water per gram of flakes.

Hot Paste Viscosity (HPV) and Cold Paste Viscosity (CPV)

[0067] The hot paste viscosity (HPV) is a measurement of the highestviscosity peak of a starch material after applying high temperaturesunder constant shear rate. The initial part of the viscosity profilecurve strongly correlates to WAI. For native starches, the hot pasteviscosity profile will show a maximum peak viscosity in the range of thegelatinization temperature. In the case of potato flakes, as well asother partially gelatinized starches, the HPV is used as an indicationof the degree of cooking and cell damage. The higher HPV profilesindicate more cell damage due to overcooking in the flaking process[FIG. 5]. Large differences between HPV and cold paste viscosityindicate uneven cooking [FIG. 5] in the flakes of the present inventionThe difference between the HPV and CPV is preferably 150 BU, morepreferably less than about 120 Brabender Units (BU), and even morepreferably less than about 100 BU. These differences indicate evencooking [FIG. 5 “control”].

[0068] Cold paste viscosity (CPV) is a measurement of the highest peakviscosity of a starch material at low temperatures under a constantshear rate. The cooling part of the viscosity profile curve stronglycorrelates to the free amylose level in the sample. For overcookedstarches, the CPV increases [FIG. 5]. The cooling curve is an indicationof the starch retrogradation happening during the process. The HPV andCPV are measured in Brabender Units (BU) which is an arbitrary unit ofviscosity measurement, roughly correlating to centipoise.

[0069] Dehydrated potato flakes made from raw potato pieces have a CPVof from about 240 by to about 320 BU, preferably from about 260 by toabout 300 BU, and more preferably from about 275 by to about 290 BU; anda CPV of from about 120 by to about 230 BU, preferably from about 150 byto about 220 BU and more preferably from about 170 by to about 210 BU.

[0070] Dehydrated potato flakes made from pre-conditioned potato pieceshave a HPV of from about 100 to about 280 BU, preferably 150 by to about250 BU and more preferably from 190 by to about 230 BU; and a CPV offrom about 100 by to about 200, preferably from about 120 by to about210 by and more preferably 140 by to about 160. Analysis of the HPV andCPV prepared by prior art processes dehydrated potato flakes have a HPVand CPV that increase over time. In contrast to flakes of the presentinvention, flakes prepared by prior art processes have HPV and CPVdifferences of greater than 120 bU's as compared to flakes of thepresent invention.

Particle Size Distribution

[0071] The particle size of the dehydrated potato flakes of the presentinvention is reduced such that from 60% to about 70% remain as a #100U.S. screen, from a 20% to about 40% remain on a #40 U.S. screen, fromabout 1 to about 3% remain on a #20 U.S. screen and from 1% to about 3%remain on a #16 U.S. screen. Particle size distribution is a measure ofthe granularity of the flakes. It is generally a weight-baseddistribution of flakes based on the size of particles. Normally, it isdescribed by a set of U.S. standard measure sizes. Reducing the size ofthe dehydrated flakes such that there are more fines can change thephysical properties of the flake. For example, reducing the particlesize results in an increased amylose content and an increase in thenumber of broken cells, as well as a change in WAI.

Dough

[0072] Another embodiment of the present invention includes using thedehydrated flake in a composition for dough. The dough can be used tomake fabricated farinaceous food products. The addition of thedehydrated flakes to the dough increases the sheet strength of the doughand gives food processors flexibility to control the properties of thedough and final products made from the dough.

[0073] Typically, the dough is used to make fabricated potato chips.However, the dough can also be used to make other farinaceous productswhich are sheeted or extruded (e.g., chips, tortilla chips, pretzels,crackers and the like, hereinafter referred to as “snacks”). The doughcomposition of the present invention comprise:

[0074] (a) from about 50% to about 70% of a starch-based materialwherein said starch-based material comprises up to 100% potato flakes ofthis invention;

[0075] (b) at least about 3% hydrolyzed starches having a D.E. of fromabout 5 to about 30; and

[0076] (c) from about 20% to about 46.5% added water.

[0077] Optionally, from about 0.5% to about 6% of emulsifier may beadded to the dough compositions as a processing aid.

[0078] The doughs of the present invention additionally have a sheetstrength between about 140 and 625 grams force (gf).

[0079] The doughs of the present invention can comprise from about 50%to about 70%, preferably from about 55% to about 65%, and morepreferably about 60% of a starch-based material. The starch-basedmaterial can comprise from about 25 to 100% potato flakes of the presentinvention, with the balance (i.e., from 0% to about 75%) being otherstarch-containing ingredients such as potato flour, potato granules,corn flour, masa corn flour, corn grits, corn meal, rice flour, tapioca,buckwheat flour, rice flour, oat flour, bean flour, barley flour,tapioca, as well as modified starches, native starches, and dehydratedstarches, starches derived from tubers, legumes and grain, for examplecornstarch, wheat starch, rice starch, waxy corn starch, oat starch,cavassa starch, waxy barley, waxy rice starch, glutinous rice starch,sweet rice starch, amioca, potato starch, tapioca starch, cornstarch,oat starch, cassaya starch, rice starch, wheat starch, and mixturesthereof. The starch-based material preferably comprises from about 40%to about 90%, more preferably from about 50% to about 80%, and even morepreferably about 60% to about 70%, potato flakes of the presentinvention, and from about 10% to about 60%, preferably from about 20% toabout 50%, and more preferably from about 30% to about 40%, of theseother starch-containing ingredients.

[0080] Particularly preferred starch-based materials of the presentinvention are made from dehydrated potato flakes of the presentinvention and potato granules wherein the potato flakes comprise fromabout 25% to about 95%, preferably from about 35% to about 90%, and morepreferably from about 45% to about 80% of the starch-based material, andthe potato granules comprise from about 5% to about 75%, preferably fromabout 10% to about 65%, and more preferably from about 20% to about 55%,of the starch-based material.

[0081] Another preferred embodiment can be made using a mixture of thepotato flakes of the present invention and potato granules, combinedwith other starch-containing ingredients that are not potato flakes orgranules. Typically, the combined flakes and granules comprise fromabout 40% to about 90%, preferably from about 50% to about 80%, and morepreferably from about 60% to about 70% of the starch-based material,while the other non potato flake/granule starch-containing ingredientscomprise from about 10% to about 70%, preferably from about 20% to about50%, and more preferably from about 30% to about 40%, of thestarch-based materials.

[0082] The dough compositions of the present invention comprise fromabout 20% to about 46.5% added water, preferably from about 22% to about40%, and more preferably from about 24% to about 35%, added water. Asused herein, the term “added water” refers to water which has been addedto the dry dough ingredients. Water which is inherently present in thedry dough ingredients, such as in the case of the sources of flour andstarches, is not included in the added water. The level of water inflours and starches is usually from about 3% to about 8%. However, ifthe maltodextrin or corn syrup solids are added as a solution or syrup,the water in this syrup or solution must be accounted for as “addedwater”. The amount of added water includes any water used to dissolve ordisperse ingredients, as well as water present in corn syrups, etc.

[0083] In addition to the starch-based material and water, the doughcompositions comprise other ingredients that aid in processability.These ingredients are particularly important when processing a doughthat is to be sheeted on a continuous basis. The additional ingredientsinclude, but are not limited to, hydrolyzed starches and emulsifiers.

[0084] Hydrolyzed starches are important to the processability of thedoughs of the present invention which have relatively low water levels.In the absence of hydrolyzed starches, low moisture levels in the dough;can prevent formation of a continuous, smooth extensible dough sheet;can hinder subsequent expansion of the dough pieces during frying; andaffects the elasticity of the dough. Although the dough compositions canbe sheeted without the inclusion of hydrolyzed starches, the resultingsnack has a foamy texture and high fat. Hydrolyzed starches reduce thework input to the dough, reducing the amount of water needed to sheetthe dough. This in turn reduces fat.

[0085] Hydrolyzed starches can be included in the dough compositions inan amount of at least about 3%, with a usual range of from about 3% toabout 15%. Preferably, hydrolyzed starches are included in an amount offrom about 5% to about 12%. Suitable hydrolyzed starches for inclusionin the dough include maltodextrins and corn syrup solids. The hydrolyzedstarches for inclusion in the dough have Dextrose Equivalent (D.E.)values of from about 5 to about 30, preferably from about 10 to about20. Maltrin™ M050, M100, M150, M180, M200, and M250 (available fromGrain Processing Corporation, Iowa) are preferred maltodextrins. TheD.E. value is a measure of the reducing equivalence of the hydrolyzedstarch referenced to dextrose and is expressed as a percentage (on a drybasis). The higher the D.E. value, the more reducing sugars are present.

[0086] Emulsifiers

[0087] Another ingredient that can be added optionally to the doughcompositions to aid in the processability of the dough is an emulsifier.The emulsifier works via several mechanisms. The first is as a coatingof the flour in the mixer just prior to the addition of the water. Thislimits the moisture absorption of the flour producing a “short” dough.The second function of the emulsifier is to create a dispersion of fatand moisture droplets throughout the dough. Both of these mechanism tendto limit the adhesiveness of the starch contained in the flour,preventing permanent adhesion to the sheeting rolls.

[0088] An emulsifier is preferably added to the dough composition priorto sheeting the dough. The emulsifier can be dissolved in a fat or in apolyol fatty acid polyester, preferably a sucrose fatty acid polyestersuch as Olean™, available from The Procter and Gamble Company. Suitableemulsifiers include mono- and diglycerides, diacetyl tartaric acidesters and propylene glycol mono- and diesters and polyglycerol.Polyglycerol emulsifiers such as monoesters of polyglycerols, preferablyhexapolyglycerols can be used.

[0089] Particularly preferred emulsifiers comprise a blend of from about42.5% to about 90%, preferably from about 50% to about 85%, morepreferably from about 60% to about 80%, non-digestible fat with thebalance being a mixture of diglyceride, triglyceride, and preferably amonoglyceride wherein the level of monoglyceride is at least about 30%,and is typically from about 30% to about 95%, preferably from about 50%to about 90% wherein the monglyceride has an IV of greater than about60, preferably an IV between about 70 to about 120, more preferably anIV of from about 80 to about 110, even more preferably an IV of fromabout 90 to about 100.

[0090] Preferably, the mono-glyceride is a distilled monoglyceridehaving an IV of about 60, derived from, for example, soybean oil,rapeseed oil, cottonseed oil, sunflower seed oil, palm oil, palm olein,safflower oil, corn oil, peanut oil and mixtures thereof. The preferreddistilled monoglycerides include but are not limited to monoglyceridesderived from, soybean oil, rapeseed and palm oil and mixtures thereof.

[0091] Typically commercially available mono-glycerides contain varyingamounts of di- and tri-glycerides. For example, distilledmonodiglyceride comprise about 90% monoglyceride while monodiglyceridescomprise about 30% mono-glycerides. Either can be used in the doughfomulations of the present invention.

[0092] A particularly preferred monoglyceride is sold under the tradenames of Dimodan® available from Danisco, New Century, Kans. and DMG 70,available from Archer Daniels Midland Company, Decatur, Ill.

[0093] The level of added emulsifier depends on the amount of work inputthat the dough will receive in subsequent processing (e.g., extrusion,sheeting) steps. As used herein, the term “added emulsifier” refers toan emulsifier which has been added to the dry dough ingredients.Emulsifiers which are inherently present in the dry dough ingredients,such as in the case of the potato flakes, are not included in the term“added emulsifier.”

[0094] The need for higher levels of emulsifier increases as work inputincreases. Typically, if the doughs are to be sheeted, emulsifiers areadded to the dough in an amount of from about 0.5% to about 6.0% byweight, preferably from about 1.0% to about 5.0%, more preferably fromabout 2 to about 4% and most preferably about 3%. Emulsifiers levelshigher than this result in sheet tears and pinholes.

[0095] Additional Ingredients

[0096] Additional ingredients can also be added to the doughcompositions. These ingredients include vitamins, salt, flavorings,flavor potentiators, and/or seasonings. Particularly preferred is theuse of Vitamin C. Vitamin C can be present in the dough compositions ata level of from about 0.01% to about 0.10%, preferably at a level offrom about 0.02% to about 0.08%, more preferably at a level of fromabout 0.03% to about 0.07%, and even more preferably at a level of fromabout 0.04% to about 0.06%. Preferably the dough is fortified such thatthe final snack comprise from about 2 mg. to about 8 mg., preferablyfrom about 4 mg. to about 6 mg. of Vitamin C per one ounce serving ofsnack. The additional ingredients can be included in the dough orsprinkled or sprayed on the surface of the snack after frying.

[0097] Sheet Strength

[0098] The dough compositions containing the potato flakes of thepresent invention exhibit substantially improved sheet strength ascompared to doughs of the same composition made with prior conventionalpotato flakes. The sheet strength is a measurement of the force neededto break a piece of dough. The sheet strength correlates withcohesiveness of the dough and the ability of the dough to resistdeveloping holes and/or tearing during subsequent processing steps.

[0099] The sheet strength of the doughs of the present inventionincreases as the amount of energy input during the dough making stepincreases. Factors which can affect energy input include, but are notlimited to, mixing conditions, dough sheet formation, and the amount ofmeasurable amylose. For example, doughs mixed in a conventional low workinput mixer, for example a Hobart® or Cuisinart® will typically have asheet strength between about 140 to about 250 depending on whether thestarting potato has been pre-conditioned or not [FIG. 1].

[0100] Dough compositions receiving relatively low work input comprisingpotato flakes made from raw potato pieces typically have a sheetstrength measurement of from about 170 gf to about 250 gf, preferablyfrom about 180 gf to about 240 gf, and more preferably from about 190 gfto about 220 gf.

[0101] Dough compositions receiving relatively low work input comprisingpotato flakes made from pre-conditioned potato pieces typically have asheet strength measurement of from about 140 gf to about 200 gf,preferably from about 155 gf to about 190 gf, and more preferably fromabout 165 gf to about 185 gf.

[0102] Doughs produced on a commercial scale where higher work inputmixers, for example a Turboilizer® or extruder are used, the sheetstrength is generally about 1.5 times to about 2.5 times the sheetstrength of the doughs produced from the low work input mixer.

[0103] As shown in FIG. 2, doughs made under same work input usingconventionally made flakes have a sheet strength lower than the doughsof the present invention.

[0104] Preferably, doughs produced from a high work input mixer have asheet strength between about 210 and about 625 gf, preferably from about225 gf and about 560 gf, more preferably from about 245 gf and about 500gf, even more preferably from about 265 gf to about 480 gf, andespecially preferably from about 200 gf to about 400 gf.

[0105] A. Dough Preparation

[0106] The dough compositions of the present invention can be preparedby any suitable method for forming sheetable doughs. Typically, a loose,dry dough is prepared by thoroughly mixing together the flakes, granulesand other starch-based materials and optionally an emulsifier andsucrose fatty acid polyester combination. A water pre-blend of flavoring(optional), hydrolyzed starches, sucrose and/or salt are separatelymixed to obtain the previously defined hydrolyzed starch and waterlevels. The water pre-blend is then added to the starch-based materialmixture and emulsifier blend. Preferred devices for mixing together thedough ingredients are conventional mixers. Hobart® mixers are used forbatch operations and Turbolizer® mixers can be used for continuousmixing operations. However, extruders can also be used to mix the doughand to form the sheets or shaped pieces.

[0107] B. Sheeting, Snack Piece Formation and Frying

[0108] Once prepared, the dough is then formed into a relatively flat,thin sheet. Any method suitable for forming such sheets fromstarch-based doughs can be used. For example, the sheet can be rolledout between two counter rotating cylindrical rollers to obtain auniform, relatively thin sheet of dough material. Any conventionalsheeting, milling and gauging equipment can be used. The mill rollsshould be heated to about 90° F. (32° C.) to about 135° F. (57° C.). Ina preferred embodiment, the mill rolls are kept at two differenttemperatures, with the front roller being cooler than the back roller.

[0109] Dough compositions of the present invention are usually formedinto a sheet having a thickness of from about 0.015 to about 0.10 inches(from about 0.038 to about 0.25 cm), and preferably to a thickness offrom about 0.05 to about 0.10 inches (from about 0.013 to about 0.025cm), and most preferably from about 0.065 inches to about 0.080 inches(1.65 to 2.03 mm). For rippled (wavy shaped) chips, the preferredthickness is about 0.75 inches (1.9 mm). The dough sheet is then formedinto snack pieces of a predetermined size and shape. The snack piecescan be formed using any suitable stamping or cutting equipment. Thesnack pieces can be formed into a variety of shapes. For example, thesnack pieces can be in the shape of ovals, squares, circles, a bowtie, astar wheel, or a pin wheel. The pieces can be scored to make rippledchips as described in published PCT application WO 95/07610, Dawes etal., Jan. 25, 1996, which is incorporated by reference.

[0110] After the snack pieces are formed, they are cooked until crisp.The snack pieces may be cooked by baking, frying, and combinationsthereof. For example the chips can be fried only, baked only, partiallyfried then baked or partially baked then fried.

[0111] The snack pieces may be baked at a temperature between about 300°F. (149° C.) to about 450° F. (232° C.) for a time sufficient to form askin the surface of the chips, and then fried to doneness. If desired,the snack pieces can also be fried to moisture content of 10% or lessand then heated with hot air, superheated steam or inert gas to lowerthe moisture level to 4% or less. This is a combined frying/baking step.

[0112] It is preferred to fry the snack pieces in oil at temperaturesfrom about 275° F. (135° C.) and about 400° F. (204° C.), preferablyfrom about 300° F. (149° C.) to about 375° F. (191° C.), and morepreferably from about 315° F. (157C) to about 350° F. (177C) for a timesufficient to form a product having from about 0.5% to about 6%,preferably from about 1% to about 5%, and more preferably from about 2%to about 4% moisture. The exact fry time is controlled by thetemperature of the frying fat and the starting water content. The frytime and temperature can be easily determined by one skilled in the art.

[0113] Preferably the snack pieces are fried in frying fat using acontinuous frying method and are constrained during frying. Thisconstrained frying method and apparatus is described in U.S. Pat. No.3,626,466 (Liepa, 1971). The shaped, constrained pieces are passedthrough the frying medium until they are fried to a crisp state with afinal moisture content of about 0.5% to about 4% water, preferably 1% to2%.

[0114] Continuous frying or batch frying of the snack pieces in anon-constrained mode is also acceptable. In this method, the pieces areimmersed in the frying fat on a moving belt or basket.

[0115] The frying can be done in convention triglyceride oils, or, ifdesired, the frying can be done in low calorie fat-like materials suchas those described in U.S. Pat. No. 3,600,186 to Mattson et al.(assigned to The Procter & Gamble Co), issued May 12, 1970; U.S. Pat.No. 4,005,195 to Jandacek (assigned to The Procter & Gamble Co.), issuedJan. 25, 1977; U.S. Pat. No. 4,005,196 to Jandacek et al. (assigned toThe Procter & Gamble Co.), issued Jan. 25, 1977; U.S. Pat. No. 4,034,083to Mattson (assigned to The Procter & Gamble Co.), issued Jul. 5, 1977;and U.S. Pat. No. 4,241,054 to Volpenhein et al. (assigned to TheProcter & Gamble Co.), issued Dec. 23, 1980, all of which areincorporated by reference herein. Frying can also be done in mixtures ofconventional triglyceride oils and non-digestible oils.

[0116] The terms “fat” and “oil” are used interchangeably herein unlessotherwise specified. The terms “fat” or “oil” refer to edible fattysubstances in a general sense, including natural or synthetic fats andoils consisting essentially of triglycerides, such as, for examplesoybean oil, corn oil, cottonseed oil, sunflower oil, palm oil, coconutoil, canola oil, fish oil, lard and tallow, which may have beenpartially or completely hydrogenated or modified otherwise, as well asnon-toxic fatty materials having properties similar to triglycerides,herein referred to as non-digestible fat, which materials may bepartially or fully indigestible. Reduced calorie fats and ediblenon-digestible fats, oils or fat substitutes are also included in theterm.

[0117] The term “non-digestible fat” refers to those edible fattymaterials that are partially or totally indigestible, e.g., polyol fattyacid polyesters, such as OLEAN™.

[0118] The terms “fat” or “oil” also refer 100% non-toxic fattymaterials having properties similar to triglycerides. The terms “fat” or“oil” in general include fat-substitutes, which materials may bepartially or fully non-digestible.

[0119] By “polyol” is meant a polyhydric alcohol containing at least 4,preferably from 4 to 11 hydroxyl groups. Polyols include sugars (i.e.,monosaccharides, disaccharides, and trisaccharides), sugar alcohols,other sugar derivatives (i.e., alkyl glucosides), polyglycerols such asdiglycerol and triglycerol, pentearythritol, sugar ethers such assorbitan and polyvinyl alcohols. Specific examples of suitable sugars,sugar alcohols and sugar derivatives include xylose, arabinose, ribose,xylitol, erythritol, glucose, methyl glucoside, mannose, galactose,fructose, sorbitol, maltose, lactose, sucrose, raffinose, andmaltotriose.

[0120] By “polyol fatty acid polyester” is meant a polyol having atleast 4 fatty acid ester groups. Polyol fatty acid esters that contain 3or less fatty acid ester groups are generally digested in, and theproducts of digestion are absorbed from, the intestinal tract much inthe manner of ordinary triglyceride fats or oils, whereas those polyolfatty acid esters containing 4 or more fatty acid ester groups aresubstantially non-digestible and consequently non-absorbable by thehuman body. It is not necessary that all of the hydroxyl groups of thepolyol be esterified, but it is preferable that disaccharide moleculescontain no more than 3 unesterified hydroxyl groups for the purpose ofbeing non-digestible. Typically, substantially all, e.g., at least about85%, of the hydroxyl groups of the polyol are esterified. In the case ofsucrose polyesters, typically from about 7 to 8 of the hydroxyl groupsof the polyol are esterified.

[0121] The polyol fatty acid esters typically contain fatty acidradicals typically having at least 4 carbon atoms and up to 26 carbonatoms. These fatty acid radicals can be derived from naturally occurringor synthetic fatty acids. The fatty acid radicals can be saturated orunsaturated, including positional or geometric isomers, e.g., cis- ortrans-isomers, and can be the same for all ester groups, or can bemixtures of different fatty acids.

[0122] Liquid non-digestible oils can also be used in the practice ofthe present invention. Liquid non-digestible oils have a completemelting point below about 37° C. include liquid polyol fatty acidpolyesters (see Jandacek; U.S. Pat. No. 4,005,195; issued Jan. 25,1977); liquid esters of tricarballylic acids (see Hamm; U.S. Pat. No.4,508,746; issued Apr. 2, 1985); liquid diesters of dicarboxylic acidssuch as derivatives of malonic and succinic acid (see Fulcher; U.S. Pat.No. 4,582,927; issued Apr. 15, 1986); liquid triglycerides ofalpha-branched chain carboxylic acids (see Whyte; U.S. Pat. No.3,579,548; issued May 18, 1971); liquid ethers and ether esterscontaining the neopentyl moiety (see Minich; U.S. Pat. No. 2,962,419;issued Nov. 29, 1960); liquid fatty polyethers of polyglycerol (SeeHunter et al; U.S. Pat. No. 3,932,532; issued Jan. 13, 1976); liquidalkyl glycoside fatty acid polyesters (see Meyer et al; U.S. Pat. No.4,840,815; issued Jun. 20, 1989); liquid polyesters of two ether linkedhydroxypolycarboxylic acids (e.g., citric or isocitric acid) (see Huhnet al; U.S. Pat. No. 4,888,195; issued Dec. 19, 1988); various liquidesterfied alkoxylated polyols including liquid esters ofepoxide-extended polyols such as liquid esterified propoxylatedglycerins (see White et al; U.S. Pat. No. 4,861,613; issued Aug. 29,1989; Cooper et al; U.S. Pat. No. 5,399,729; issued Mar. 21, 1995;Mazurek; U.S. Pat. No. 5,589,217; issued Dec. 31, 1996; and Mazurek;U.S. Pat. No. 5,597,605; issued Jan. 28, 1997); liquid esterifiedethoxylated sugar and sugar alcohol esters (see Ennis et al; U.S. Pat.No. 5,077,073); liquid esterified ethoxylated alkyl glycosides (seeEnnis et al; U.S. Pat. No. 5,059,443, issued Oct. 22, 1991); liquidesterified alkoxylated polysaccharides (see Cooper; U.S. Pat. No.5,273,772; issued Dec. 28, 1993); liquid linked esterifled alkoxylatedpolyols (see Ferenz; U.S. Pat. No. 5,427,815; issued Jun. 27, 1995 andFerenz et al; U.S. Pat. No. 5,374,446; issued Dec. 20, 1994); liquidesterfied polyoxyalkylene block copolymers (see Cooper; U.S. Pat. No.5,308,634; issued May 3, 1994); liquid esterified polyethers containingring-opened oxolane units (see Cooper; U.S. Pat. No. 5,389,392; issuedFeb. 14, 1995); liquid alkoxylated polyglycerol polyesters (see Harris;U.S. Pat. No. 5,399,371; issued Mar. 21, 1995); liquid partiallyesterified polysaccharides (see White; U.S. Pat. No. 4,959,466; issuedSep. 25, 1990); as well as liquid polydimethyl siloxanes (e.g., FluidSilicones available from Dow Corning). All of the foregoing patentsrelating to the liquid nondigestible oil component are incorporatedherein by reference. Solid non-digestible fats or other solid materialscan be added to the liquid non-digestible oils to prevent passive oilloss. Particularly preferred non-digestible fat compositions includethose described in U.S. Pat. No. 5,490,995 issued to Corrigan, 1996,U.S. Pat. No. 5,480,667 issued to Corrigan et al, 1996, U.S. Pat. No.5,451,416 issued to Johnston et al, 1995 and U.S. Pat. No. 5,422,131issued to Elsen et al, 1995. U.S. Pat. No. 5,419,925 issued to Seiden etal, 1995 describes mixtures of reduced calorie triglycerides and polyolpolyesters that can be used herein. However the latter composition mayprovide more digestible fat.

[0123] The preferred non-digestible fats are fatty materials havingproperties similar to triglycerides such as sucrose polyesters. OLEAN,™a preferred non-digestible fat, is made by The Procter and GambleCompany. These preferred non-digestible fats or oil substitutecompositions are described in Young; et al., U.S. Pat. No. 5,085,884,issued Feb. 4, 1992, and U.S. Pat. No. 5,422,131, issued Jun. 6, 1995 toElsen et al.

[0124] Other ingredients known in the art may also be added to theedible fats and oils, including antioxidants such as TBHQ ascorbic acid,chelating agents such as citric acid, and anti-foaming agents such asdimethylpolysiloxane.

[0125] The snack products made from this process typically have fromabout 19% to about 38%, preferably from about 20% to about 35%, and morepreferably from about 23% to about 32% fat. If a higher fat level isdesired in the snack product to further improve the lubricity of thesnack, oil can be sprayed onto the snack product when it emerges fromthe fryer, or when it is removed from the mold used in constrainedfrying. Preferably the oils for spraying will have an iodine valuegreater than 75, and most preferably above 90. Oils with characteristicflavors or highly unsaturated oils can be sprayed onto the snackproduct. Oils with added flavors can also be used. These include butterflavored oils, natural or artificial flavored oils, herb oils and oilswith garlic or onion flavors added. This is a way to introduce a varietyof flavors without having the flavor undergo browning reactions duringthe frying. It also avoids adding the flavor to the dough and having theflavor react with or leach into the oil during the frying process. Thismethod can be used to introduce healthier oils which would ordinarilyundergo polymerization or oxidation during the heating necessary to frythe snacks.

[0126] Oil spray can be applied to the snack product after baking orfrying. The oil may be used to increase the fat content of the snack toa fat content as high as 44% oil. Thus a snack product having variousfat contents can be made using this additional step.

Analytical Methods

[0127] Water Absorption Index (WAI)

[0128] In general, the terms “Water Absorption Index” and “WAI” refer tothe measurement of the water-holding capacity of any carbohydrate basedmaterial as a result of a cooking process. (See for example Anderson, R.A., Conway, H. F., Pfeifer, V. F. and Griffin, Jr., E. L., 1969,Gelatinization of Corn Grits By Roll- and Extrusion-Cooking. CEREALSCIENCE TODAY; 14(1):4). The cooking and dehydration of potato flakesintroduces changes in the potato cell physiology which affects itsrehydration properties, specifically its water-holding capacity. Thismeasurement is typically expressed as the ratio of mass of water heldper unit mass of material.

[0129] The WAI for a sample is determined by the following procedure:The weight to two decimal places of an empty centrifuge tube isdetermined. Two grams of dry sample (e.g., potato flakes) are placedinto the tube. Thirty milliliters of water is added to the tube. Thewater and sample are stirred vigorously to insure no dry lumps remain.The tube is placed in a 30° C. (85° F.) water bath for 30 minutes,repeating the stirring procedure at 10 and 20 minutes. The tube is thencentrifuged for 15 minutes at 3,000 RPM. The water is then decanted fromthe tube, leaving a gel behind. The tube and contents are weighed. TheWAI is calculated by dividing the weight of the resulting gel by theweight of the dry sample (i.e., [weight of tube and gel]−[weight oftube]÷[weight of dry flakes]).

[0130] Percent Amylose (A %) Test

[0131] This method is designed to measure the percentage (relativequantity) of amylose in potato flakes which is soluble in 0.1N NaOHsolution under specific test conditions. Flakes are stirred in a basesolution at 60° C. for 30 minutes, centrifuged, and the clearsupernatant is then reacted with iodine and analyzedspectrophotometrically. The amylose is measured as the iodine complexesat 700 nm, rather than 610 nm, to avoid the interference from the“amylopectin-I₂ complex”.

[0132] Apparatus

[0133] Volumetric flakes, volumetric pipettes, balance,spectrophotometer (Beckman Model 24 or equivalent), cells (1 cmdisposable, Marksman Science #1-P-10, or 1 cam sipper type MarksonMB-178 or Beckman Part #579215), constant temperature bath, blender andblender jars.

[0134] Reagents

[0135] Sodium Hydroxide Solution 0.1N, Hydrochloric Acid, Iodine,Potassium Iodide, Calibration Standard (Amylose—Sigma Type III potatocat. #A-0512).

[0136] Preparation of Solutions

[0137] A. Stock Iodine Solution

[0138] Weigh 2 g of Iodine and 20 g of Potassium Iodide into a red 250ml volumetric flask, and dissolve with distilled water.

[0139] B. Reagent Iodine Solution

[0140] Pipet 10 ml of the stock Iodine solution and 2 ml of concentratedhydrochloric acid into a red 1000 ml volumetric flask. Dilute to volumewith distilled water.

[0141] Standard Curve Preparation Using Standard Amylose

[0142] 1. Dissolve 1 g of amylose (Sigma, from potato) with 100 0.1NNaOH. Transfer entire solution into a centrifuge bottle, withoutrinsing. Centrifuge at 1600 rpm for 15 min.

[0143] 2. Prepare three dilutions: a) 10 ml of supernatant into 100 mlof 0.1N NaOH, b) 5 ml of supernatant of first dilution into 100 ml of0.1N NaOH, and c) 50 ml of the second dilution into 100 ml of 0.1N NaOH.

[0144] Sample Preparation

[0145] 1. Obtain percent moisture in each sample. (Vacuum oven 16 hours70° C., or 3 hr @130° C. in an air oven).

[0146] 2. Weigh 0.2 g of potato flakes and dissolve with 100 ml of 0.1 NNaOH solution. Turn the stirrer on high to obtain a good vortex in theliquid.

[0147] 3. Place samples in the 60° C. water bath. Stir for 30 minutes.Remove from bath.

[0148] 4. Pour the entire solution into a centrifuge bottle; do notrinse. Centrifuge at 1600 rpm for 15 minutes.

[0149] 5. Pipet 1 ml of the supernatant into a 25 ml volumetric flask.Dilute all the volume with iodine reagent. Prepare the blank solution,using 1 ml of the 0.1N NaOH solution in a 25 ml flask. Shake well. Thecolorimetric determination must be made 10-30 minutes after mixing.

[0150] Colorimetric Determination

[0151] Set the wavelength to 700 nm. Zero the instrument with distilledwater in the sample cell and in the reference beam. Fill the sample cellwith blank solution and read against distilled water. Note this valueand subtract from each sample value. In normal practice, the absorbancesfalls between 0.02 and 0.8 absorbance units.

[0152] Calculations (Using the Standard Amylose):

[0153] Plot a curve using g/l 00 ml of standard concentrations as the xaxis versus the absorbance @700 nm as the y axis.${\% \quad {Amylose}} = {\frac{\frac{\left( {{Amylose}\quad g\text{/}100\quad {ml}} \right)}{\left( {100 - {\% \quad {water}}} \right) \times \left( {{Sample}\quad {{wt}.}} \right)}}{100} \times 100}$

[0154] Percent of Broken Cells Test

[0155] The percent of broken cells in the potato flakes and the averagesize of the cells is determined by simple observation through the lightmicroscope. A small amount of flakes is spread on a portaglass, and 2-3drops of water are added immediately. After 30 sec., the sample is readyto be observed through the light microscope (×100). The % broken cellsare determined.

[0156] Hot Paste and Cold Paste Viscosities

[0157] Accurately weigh 30 g of flakes on a moisture free basis andtransfer quantitatively to a 600 ml beaker. Add about 400 ml of water tothe flakes sample and mix thoroughly to obtain a homogeneous suspension.The dispersion is transferred to the sample cup of an amylograph and theinstrument head is lowered into the operating position. Start theamylograph with the thermo-regulator transport switch in the neutralposition, heat off, and the cup speed at 75 rpm. Heat at a rate of 1.5°C. per min. until the sample reaches 90° C. The thermo-regulator switchis set at neutral and held at 90° C. for 10 min. This is the hot pasteviscosity. Then the thermo-regulator switch is changed to cool at 1.5°C. per minute to 50° C. This is the cold paste viscosity. (TheAmylograph Handbook, edited by William C. Shuey and Keith H. Tipples,AACC, 1994.) Hot and cold paste viscosities are measured in BrabenderUnits (BU).

[0158] Particle Size Distribution Test

[0159] 1. Weigh dehydrated potatoes.

[0160] 2. Weigh the screens and then stack them in the following ordertop to bottom: U.S. #16, #20, #40, #100 and bottom pan. Pour in thedehydrated potatoes. Put the screens in a rotap unit. Turn on the rotapunit for one minute.

[0161] 3. Weigh and record the total weight of potato material on thescreens.

[0162] Sheet Strength Test

[0163] The sheet strength is determined as follows: Sheet strength isthe measurement of the force needed to break a dough sheet of 0.635 mm.The sheet strength is read as the maximum peak force (gf) of a graphobtained from force against distance. The test is designed to measurepotato dough sheet strength. All products are tested at roomtemperature. Sheet strength is an average of ten repetitions of eachtest. The sheet strength is measured by preparing a dough comprising:

[0164] a) 200 g of solids;

[0165] b) 90 g of water; and

[0166] c) 0.5 g of distilled mono and diglyceride of partiallyhydrogenated soybean oil emulsifier available from Quest.

[0167] The dough is made in a small Cuisinart® mixer at low speed for10-20 seconds. After mixing the dough is sheeted using a conventionalmilling machine to a thickness of 0.635 mm (22 mils). The mill rolls areusually 1.2 meter length x 0.75 diameter meter.

[0168] This test is conducted using a Texture Analyzer (TA-XT2) fromTexture Technologies Corp. This equipment uses a software called XTRAD.This test utilizes a {fraction (7/16)}″ diameter acrylic cylinder probe(TA-108), which has a smooth edge to minimize any cutting of the doughsheet. The dough sheet is held between two aluminum plates (10×10 cm).The aluminum plates have a 7 cm diameter opening in the center. Throughthis opening the probe makes contact with the sheet and pushes itdownwards until it breaks. These plates have an opening in each cornerto hold the sheet dough in place. Each dough sheet is pre-punched withholes to fit over the alignment pins at the corners of the plate and cutto the size (10×10 cm) of the plate. This provides uniform tension asthe probe moves down and through the sheet. The probe travels at 2mm/second until the dough sheet surface is detected at 20 grams offorce. The probe then travels at 1.0 mm/second for up to 50 mm, adistance chosen to stretch the dough sheet until it thoroughly ruptures.The probe withdraws at 10.0 mm/second. The probe is run in a “Force vsCompression” mode, which means the probe will move downward measuringthe force.

[0169] The embodiments of the present invention are illustrated by thefollowing examples.

EXAMPLES 1-3

[0170] Examples 1-3 are prepared from (1) pre-conditioned potato slabs,(2) a combination of slabs, slivers and nubbins and (3) slivers andnubbins. The potato pieces are processed according to the method of thepresent invention. The potato mash is drum dried. The physicalproperties of the dehydrated flakes are measured and microscopicobservations are made. The processing parameters and physical propertiesof the dehydrated potato flakes are listed in Table 1 and Table 2 below.TABLE 1 Process parameters for making dehydrated potato flakes ProcessParameters Example 1 Example 2 Example 3 % Pre-conditioned Slabs 100 600 % Slivers & nubbins 0 40 100 Cooking Pressure (PSI) 5 5 5 Cooking time(min) 19 21 23 Drum Speed (rev/sec) 10.5 10.5 10.5 Sheet Thickness (mm)0.2 0.2 0.2

[0171] TABLE 2 Physical properties of dehydrated potato flakes FlakeProperties Example 1 Example 2 Example 3 Moisture (%) 6.0 6.0 6.0 WAI7.9 8.6 8.1 Amylose (%) 20 22.0 22.5 HPV (BU)* 290 — 320 CPV (BU) 200 —220 Microscopic 50% broken cells 50% broken cells 50% broken cellsObservation

EXAMPLES 4-5

[0172] The following examples compare dehydrated potato flakes preparedaccording to a conventional process conditions to dehydrated potatoflakes prepared according to the present invention. See Table 3. The rawpotato used to produce the flakes of Example 4 is fast cooked (i.e,temperature rise of about 75° F./minute until the potato slabs reach atemperature of about 180° F.). The raw potatoes used to produce thepotato flakes of Example 5 is slow cooked (i.e., temperature rise ofabout 12° F./minute until the potato slabs reach a temperature of about180° F.). TABLE 3 Comparison of dehydrated potato flakes ProcessParameters Example 4 Example 5 % Slabs 100 100 Cooking Pressure (psi) 4510 Cooking time (min) 50 28 Drum Speed (rev/sec) 4.5 WAI 10.3 8.5Amylose (%) 8.4 22.3 HPV (BU)* 400 280 CPV (BU) 200 200

EXAMPLE 6

[0173] A dough composition is prepared from the potato flakes of thepresent invention having the physical properties listed below. The doughcomposition comprises 30% water and 70% of the following mixture ofingredients: Ingredient Wt. % in mixture Potato flakes 78 Wheat Starch 9Corn Meal 9 Malto-dextrin 4

[0174] The physical properties of dehydrated potato flakes used areshown in the following table: Flake Properties Example Moisture (%) 6.0WAI 8.5 Amylose (%) 24 HPV (BU)* 200 CPV (BU) 200 MicroscopicObservation 50% broken cells

[0175] The potato flakes, wheat starch and corn meal are blended in aTurbulizer® mixer. The maltodextrin is dissolved in the water and addedto the blend. The blend is mixed to form a loose, dry dough.

[0176] The dough is sheeted by continuously feeding it through a pair ofsheeting rolls forming an elastic continuous sheet without pin holes.Sheet thickness is controlled to 0.02 inches (0.05 cm). The dough sheetstrength is 211 gram force.

[0177] The dough sheet is then cut into oval shaped pieces and fried ina constrained frying mold at 375° F. for about 12 seconds. The fryingoil is a blend of cottonseed and corn oils. The fried pieces containabout 38% fat.

EXAMPLE 7

[0178] A dough is prepared from the following ingredients: IngredientWt. % of total formula Potato flakes (same as in example 1) 53.10 Potatogranules 5.90 Maltodextrin 4.50 Water 32.70 *Emulsifier 3.00 Sugar 0.40Salt 0.40

[0179] The maltodextrin is mixed with water to make a syrup. The syrupis added to the remaining ingredients as in Example VI to make a loose,dry dough.

[0180] The dough is sheeted by continuously feeding it through a pair ofsheeting rolls forming an elastic continuous sheet without pin holes.Sheet thickness is controlled to 0.02 inches (0.05 cm). The front rollis heated to about 90° F. (32° C.) and the back roll is heated to about135° F. (57° C.). The dough sheet is then cut into oval shaped piecesand fried in a constrained frying mold at 385° F. (196° C.) in OLEAN™ (anon-digestible fat made by The Procter and Gamble Company) for about 12seconds. The product is held in the molds for about 20 seconds to allowthe OLEAN™ to drain. The resulting product has a non-digestible fatlevel of about 30%. The digestible fat level from the emulsifier is lessthan 0.25 grams/30 gram serving.

What is claimed is:
 1. Dehydrated potato flakes, comprising: (a) fromabout 40% to about 60% broken cells; (b) from about 16% to about 27%amylose; (c) from about 5% to about 10% moisture; and (d) at least about0.1% emulsifier.
 2. Dehydrated potato flakes according to claim 1wherein said flakes comprise from about 45% to about 50% broken cells;from about 20% to about 27% amylose; from about 7% to about 8% moisture;and from about 0.2% to about 0.4% emulsifier.
 3. Dehydrated potatoflakes according to claim 1 wherein said flakes have a water absorptionindex of from about 6.7% to about 9.5 grams of water per gram of flakes.4. Dehydrated potato flakes according to claim 1 having a hot pasteviscosity of from about 100 BU to about 320 BU.
 5. Dehydrated potatoflakes according to claim 4 having a hot paste viscosity of from about240 BU to about 300 BU.
 6. Dehydrated potato flakes according to claim 4having a cold paste viscosity of from about 120 BU to about 200 BU. 7.Dehydrated potato flakes according to claim 6 having a hot pasteviscosity of from about 240 BU to about 300 BU.
 8. Dehydrated potatoflakes according to claim 7 having a cold paste viscosity of from about120 BU to about 220 BU.
 9. Dehydrated potato flakes according to claim 6having a hot paste viscosity of from about 275 BU to about 290 BU and acold paste viscosity of from about 150 BU to about 210 BU. 10.Dehydrated potato flakes according to claim 6 wherein said flakes areprepared from raw potatoes.
 11. Dehydrated potato flakes according toclaim 1 wherein said flakes comprise from about 17% to about 20%amylose; and wherein said flakes are produced from pre-conditionedpotato pieces.
 12. Dehydrated potato flakes according to claim 11 havinga water absorption index of from about 7 grams to about 9 grams of waterper gram of flakes.
 13. Dehydrated potato flakes according to claim 12having a hot paste viscosity of from about 100 BU to about 280 BU. 14.Dehydrated potato flakes according to claim 13 having a hot pasteviscosity is from about 150 BU to about 250 BU.
 15. Dehydrated potatoflakes according to claim 12 having a cold paste viscosity of from about100 BU to about 200 BU.
 16. Dehydrated potato flakes according to claim15 having cold paste viscosity is from about 120 BU to about 180 BU. 17.Dehydrated potato flakes according to claim 12 having a hot pasteviscosity of from about 190 BU to about 230 BU and a cold pasteviscosity of from about 140 BU to about 160 BU.
 18. Dehydrated potatoflakes according to claim 17 wherein said pre-conditioned pieces areselected from the group consisting of potato slabs, potato nubbins,potato slivers and mixtures thereof.
 19. A process for making dehydratedpotato flakes, which comprises the steps of: (a) cooking raw potatopieces with steam under atmospheric pressure for a time sufficient toswell the potato cells and starch granules and separate the potato cellsfrom each other without breaking more than 60% of the starch cellsinside the potato cells; (b) forming the cooked potato pieces into apotato mash; (c) drying the potato mash to a moisture content of fromabout 5% to about 10% to provide a dehydrated mash; (d) comminuting thedehydrated mash to form potato flakes.
 20. The process of claim 19wherein the steam of step (a) has a pressure of from about 2 psig toabout 50 psig.
 21. The process of claim 20 wherein the steam of step (a)has a pressure of from about 5 psig to about 18 psig.
 22. The process ofclaim 21 wherein the temperature of the potato pieces in step (a) risesfrom about 175° F. to about 212° F. over a time period of more thanabout 10 minutes.
 23. The process of claim 22 wherein the temperature ofthe potato pieces in step (a) rises from about 175° F. to about 212° F.over a time period of more than about 20 minutes.
 24. The process ofclaim 22 wherein the potato pieces are cooked in step (a) for at leastabout 30 minutes.
 25. The process of claim 24 wherein the potato piecesare cooked in step (a) for from about 30 to about 65 minutes.
 26. Theprocess of claim 19 wherein at least about 0.1% emulsifier is added tothe potato mash of step (b) prior to initiating drying process of step(c).
 27. A dough composition comprising: (a) from about 50% to about 70%of a starch-based material wherein said starch-based material comprisesfrom about 25% to about 100% potato flakes of claim 1; (b) at leastabout 3% hydrolyzed starches having a DE of from about 5 to about 30;and (c) from about 20% to about 46.5% added water.
 28. The doughcomposition of claim 27 wherein the starch-based material comprises fromabout 40% to about 90% potato flakes.
 29. The dough composition of claim27 wherein the starch-based material further comprises from about 10% toabout 60% potato granules.
 30. The dough composition of claim 28 furthercomprising from about 0.5% to about 6% of emulsifier.
 31. A doughcomposition comprising: (a) from about 50% to about 70% of astarch-based materials wherein said starch-based material comprises fromabout 25% to about 100% potato flakes of claim 9; (b) at least about 3%hydrolyzed starches having a DE of from about 5 to about 30; and (c)from about 20% to about 46.5% added water.
 32. The dough composition ofclaim 31 wherein the starch-based material comprises from about 40% toabout 90% potato flakes.
 33. The dough composition of claim 31 whereinthe starch-based material comprise from about 40% to about 90% combinedflakes and granules and from about 10% to about 60% of other starchcontaining ingredients selected from the group consisting of potatoflour, tapioca flour, peanut flour, wheat flour, oat flour, rice flour,corn flour, soy meal, corn meal, potato starch, tapioca starch,cornstarch, oat starch, cassaya starch and mixtures thereof.
 34. Thedough composition of claim 33 wherein the dough is sheetable and whereinthe dough has a sheet strength of from about 140 gf to about 625 gf. 35.The dough composition of claim 34 wherein the dough has a sheet strengthof from about 170 gf to about 250 gf.
 36. The dough composition of claim34 wherein the dough has a sheet strength of from about 155 gf to about190 gf.
 37. A fabricated chip made from the dough of claim 33 whereinthe dough is cut into snack food pieces and are cooked by baking, fryingor combinations thereof to provide a fabricated chip.
 38. The fabricatedchip of claim 37 which is fried in a non-digestible fat.
 39. A processfor making a snack comprising the steps of: (a) forming a sheetabledough comprising the dough composition of claim 33; (b) forming thedough into a sheet having a sheet strength of from about 140 gf to about250 gf; (c) cutting snack pieces from the sheet; and (d) frying thesnack pieces in a fat.
 40. The process of claim 39 wherein the dough isformed into a sheet having a thickness of from about 0.015 inches toabout 0.10 inches (from about 0.038 to about 0.25 cm).
 41. The processof claim 40 wherein the fat is a non-digestible fat.